An abscess is a localized collection of pus within the body. Abscesses are typically caused when the body tries to fight an infection within the tissues of the body, sending white blood cells to fight further infection. The blood cells collect around the initial site of infection, accumulating to form pus. As the white blood cells die and the infection increases, the surrounding healthy tissues form an “abscess wall”, or capsule, around the pus in an attempt to prevent it from infecting neighboring structures. However, this encapsulation of the pus and the abscess wall tend to prevent further immune cells from attacking bacteria in the pus, or from reaching the causative organism or foreign object.
Abscesses can develop in many parts of the body, but they often involve the skin surface. Skin abscesses are often referred to as boils. Unlike other infections, antibiotics alone may not cure a large abscess. Usually, large abscesses must open and drain to improve. Although sometimes an abscess will open and drain spontaneously, it often needs to be opened and drained (incision and drainage) by a health care provider.
The standard treatment procedure is for a doctor to use a local anesthetic to numb the affected area. A sedative may even be needed if the abscess is large. Using a scalpel, the abscess is lanced and allowed to drain, removing the pus and any other debris from the area. To minimize scarring, it can be preferable to make the incision only as large as necessary to promote drainage. Antibiotics and hot compresses are usually prescribed. Large abscesses can result in an abscess pocket remaining under the skin after all the pus is drained, which usually necessitates repeated fluid irrigation during the healing process to wash away accumulated debris, sloughed tissue, or recurring pus formation. Ideally, an abscess is allowed to heal from the inside out. Thus, once drained, the wound is kept open to facilitate periodic irrigation, continued drainage and promote proper healing. Large abscesses may be packed with sterile gauze, although there is some evidence to show that this can impede the healing process. (O'Malley, G. F. et al., (2009) “Routine Packing of Simple Cutaneous Abscesses is Painful and Probably Unnecessary,” Academic Emergency Medicine, 16(5): 470-473.)
If the area does not drain sufficiently and/or irrigation is not performed adequately, the abscess will reform. This often happens if the wound opening or abscess incision closes too soon, or if the abscess is too deep for all of the pus to drain or be irrigated from the incision. Applying pressure to the area to force the pus to drain is not recommended since that can actually force the pus deeper into the tissues, causing further damage.
Irrigation is the most common and safest procedure for cleansing and debriding open contaminated wounds. Irrigation involves the application of sterile solutions or fluids to wounds to remove loose devitalized tissue, bacterial inoculum, blood clots, loose debris, and foreign bodies proximate to and within the depths of the wound. The two critical components of any effective wound irrigation method and/or device are: (1) the application of an adequate volume of sterile irrigation solution to the wound, and (2) the use of sufficient pressure applied in an effective dispersal pattern in the delivery of the solution to effectively remove contaminants. It is not uncommon for wounds, to require a liter or more of irrigation solution. (Mulliken, John B. (1984) “Management of Wounds,” in Emergency Medicine, May ed., John Wiley & Sons, pp. 283-286.) It has also been demonstrated that stream pressure of a minimum of 4 pounds per square inch (psi) (and, preferably, 7 psi) is required to effectively flush or remove contaminants from a wound. See, for example, Rodeheaver, G. T. Wound Cleaning, Wound Irrigation, Wound Disinfection, In: Krasner, D., Kane, D. Chronic Wound Care. 2nd ed. Wayne, Pa.; Health Management Publications; 1997, pp 97-108; and Bergstrom, N., Bennett, M. A., Carlson, C. E. et al. Treatment of Pressure Ulcers. Clinical Guideline No. 15. AHCPR Publication No. 95-0652. Rockville, Md. Department of Health and Human Services. Public Health Services, Agency of Health Care Policy and Research; December 1994.)
Irrigation pressure in excess of desired limits (e.g., 25 psi or greater) may actually drive bacteria and particulate matter deeper into the wound and thereby defeat the purpose of the irrigation process. High-pressure irrigation may also cause damage to healthy tissue and impede the tissue's defenses and retard healing. Thus, effective wound irrigation requires the use and application of adequate volumes of irrigation solution delivered to the wound in an effective dispersal pattern at appropriate pressures.
Unfortunately, most irrigation devices and methods are effective only on relatively shallow wounds or larger open wounds, such as burns or large open cuts. Deeper wounds, particularly those with smaller openings, such as abscesses or puncture wounds, would obtain only minimal benefit from a surface irrigation procedure. Devices currently used to cleanse deeper wounds, such as various types of syringe models, often do not have sufficient pressure, or fluid dispersion to actually debride tissues and/or cannot deliver a sufficient amount of solution to thoroughly flush out an abscess or similar wound.
More recently, an advantageous wound irrigation system has been developed whereby a dispersed stream of irrigation fluid is easily and effectively applied to wounds. This system is described at, for example, U.S. Pat. Nos. 5,830,197 and 6,468,253 and International Patent Applications WO 00/15279 and WO 02/007799. A specific embodiment of this system is also disclosed in U.S. Design Pat. D588,692 and D556,595.
Although the use of the dispersed stream is highly advantageous for cleansing wounds, it has been determined that the shape and size of the nozzles delivering the irrigation fluid can be improved for use in irrigating puncture wounds, abscesses, and similar deep tissue wounds.